[A study on the expression of p16 protein and bcl-2 protein in cutaneous eyelid tumors]

To investigate the relationship between p16 (tumor suppressor) and bcl-2 (apoptosis inhibitor) gene expression and the incidence and development of eyelid malignant tumors.

Streptavidin-biotin-peroxidase complex immunohistochemical method was used to study the expression of p16 gene and bcl-2 gene in 96 cases with eyelid malignant tumors.

In the 96 cases, including 40 cases of basal cell carcinoma (BCC), 33 squamous and 23 sebaceous carcinomas, their p16 protein positive (nuclear staining) rates were 70.0%, 54.6% and 56.5% respectively. The p16 positive rate was negatively correlated to the degree of tumor histological differentiation, and the rate difference between the high differentiated carcinoma and the low differentiated one was significant (P < 0.05). bcl-2 protein positive expression was detected in the cytoplasm. All of the 40 BCCs were bcl-2 positive and nearly all the tumor cells showed positive cytoplasmic expression, while in the 33 specimens of squamous cell carcinoma, only did one show positive focal reaction and the staining in other 32 cases was relatively faint. None of the 23 sebaceous carcinoma expressed bcl-2.

The expression of p16 protein is related to the occurrence and degree of differentiation of eyelid malignant tumors. The over-expression of bcl-2 protein suggests that suppression of apoptosis might play a role in the tumorigenesis of BCC.